Cub had become minimally communicative during the tour, and OX did not understand this. Had he been injured during the battle with Mach?

It is the mating urge, Ornet explained, delving again into his memory-experience of mams. Sight or smell of the mature female stimulates the male to interact with her.

Why? OX inquired, finding the concept obscure.

It is the way they reproduce their kind. My kind performs similarly; Dec's has a separate mechanism. The machines are distinct from us all.

Why should any kind of being require reproduction?

We originate, we age, we die, Ornet squawked. It is the way of physical species. If we do not reproduce ourselves, there will be nothing.

Still OX could not grasp it. I do not reproduce myself. I exist as long as my elements are charged and numerous.

You surely do reproduce yourself, Ornet squawked. I have not seen enough of your type to fathom the mechanism, but my memory indicates that it must be -- for all ent.i.ties. In some way you were conceived by your forebears, and in some way you will transmit your heritage to your successors. Perhaps if you encountered a female of your species --

There are no pattern-females, OX replied. I read that in my circuits. I have the potential to become anything that any pattern can be.

Ornet drooped his tail feathers. He never engaged in speculation; the past was his primary interest.

OX sent a shoot to question Dec. Why should spots die or reproduce themselves? it flashed.

The two are synonymous, Dec replied. To die is to reproduce.

This did not satisfy OX, either. A pattern needed neither to die nor to reproduce. Why should a spot?

Dec was emitting a complex array of signals. OX adjusted his circuitry to pick up the full spectrum. Dec was capable of far greater communication than either of the others, for he used light, the fastest of radiations. OX could perceive it by the effect of his elements: minute but definite. He had long since intensified his perceptions of such variations so that observations that had once been beyond his means were now routine. Now he activated a really intricate perception network, more comprehensive and sensitive and responsive than ever before.

Then Dec's whole mind was coming across on the transmission, as clearly as if it were a barrage of pattern-radiation shoots: [DEATH] [SPORES] [MERGING] [REPRODUCTION].

* * * * [cessation] [carriers of] [two sources] [growth of cells]

[animation] [genetic code] [crossover] *

* * [chain of habitats]

[philosophical] [female male]

[ramifications]

OX a.s.similated it and fed back his questions on the aspects of the concept. The dialogue was complex, with loops of subdefinitions and commentary opening out from the corners of the major topics, with both obvious and subtle feedbacks and interactions between concepts. It required maintenance of a circuit larger than the rest of his volume. OX stayed with it, devoting whatever attention was necessary. He refined his circuits, added to them, revised...

And found himself within the mind of Dec.

Now he felt the force of gravity, a vital component of Dec's motion; the pressure of atmosphere, another essential; the impact of physical light on his eye. He felt the musculature of the single foot, opposing the constant pull and unbalance.

These things had been mere concepts to him before, described but not really understood. It was one thing to know that a physical body had weight that held it to the ground; it was quite another to experience that ubiquitous force on every cell of the body. A factor that was of no importance to OX in his natural state was a matter of life and death to this physical being; a fall could actually terminate Dec's existence! Thus, gravity equated with survival. Yet gravity was only one of an entire complex of physical forces. No wonder the spots were different in their reactions from OX; their survival depended on it!

And he understood the synonymity of death and reproduction, how the primed body dissolved into its component cells that became floating spores that met and merged with the spores of another deceased fungus ent.i.ty and then grew into new ent.i.ties. Without death there was no replication, and without replication there would be no more ent.i.ties of this type. Yet this process was necessary to the evolution of the species, and without evolution it would also pa.s.s. Death equated with survival -- death of the individual, survival of the species -- because the demands of the physical environment were always shifting. OX now understood the essential nature of these things, and the lightness of them. Multiple physical imperatives set fantastic demands, requiring complex devices of survival unknown to pattern-ent.i.ties.

Then he was out of the physical, back in his own nature, fibrillating. He had never before experienced sensation and thinking of this type; there was a phenomenal amount of data to a.s.similate and circuits to modify. The physical was a whole separate existence, with its unique imperatives!

OX had learned more in this one encounter than in any prior one. He now realized all the way through his being that the intellectual systems of the spots were as complex and meaningful as his own. The spots were, indeed, complete ent.i.ties.

He modified his circuits to incorporate a perpetual awareness and appreciation of this fact. Just as alternity was infinitely variable, so was intellect! His comprehension of existence would not be complete until he had experienced the inner nature of each spot -- and of a machine.

He formed a shoot to approach Ornet. By motions and flashes that coincided with the creature's mode of communication, OX made known his mission: to exchange minds for a moment. Ornet was receptive; he had long been curious, in a paleontological way, about the inner nature of patterns, since they had so little place in his memory.

The mechanism of exchange differed from the one that had been effective with Dec, for there was no ma.s.s-level tool of light. Instead, OX had to create a shoot-circuit that duplicated the bird's every observable contour and function, correcting it as Ornet directed. OX made himself into another Ornet, with feet and claws and wings and beak, subject to gravity and all the other manifestations of the physical aspect. Then this form moved to coincide with the presence of Ornet, and the shoot's points picked up the signals of the body's nervous functioning, the living animation of its cells.

Slowly, the mapping progressed, merging the element pattern with the physical pattern. And as the overlap became sufficient, OX began to receive Ornet's sensations and thoughts directly.

Ornet was old. His species was normally adult in the third year after hatching and faded after twenty. Ornet was twenty now. His powers were receding, his feathers losing their gloss, his beak its sharp edge. He felt a kind of vacuum in his life, but he had not been able to define it until OX had questioned him about Cub. Then his memory had been evoked, making it clear -- but far too late. He had never had contact with a female of his kind, never been aroused -- and so had lived without really missing it. He was not given to speculative thought or to emotional reactions; he accepted what was and worked only to enhance survival and comfort.

This personality, in a manner quite different from Dec's, was compatible with OX's own mode. But because Ornet's reproductive aspect was quiescent, OX still had no direct comprehension of it. And so long as his understanding was incomplete, he lacked a potential tool for survival.

It was evident that Ornet did not have to die in order to reproduce his kind. But if the death/reproduction connection were not valid, what was?

OX phased out, moving the shoot away from coincidence with the body of the bird. Deprived of their guidance by the minute electrical stimuli of the physical nervous system, the subcircuits collapsed. It was a non-survival jolt -- but only for the shoot. In a moment OX reorganized in a more stable format, recovering equilibrium.

He had absorbed another vast segment of reality and comprehended to some extent the process of aging and its relation to death. But it was not enough.

Now he came to Cub. Cub, by the reckoning of Ornet's memory, was now in the young prime of his life. And he had, as OX himself knew, a marvelously powerful and versatile reasoning mechanism. He was the source of OX's confusion; now perhaps he would be the resolution of it.

OX made another phase-in shoot, this one in the form of Cub. Small and tight as it was, this lone shoot was nevertheless far more complex than OX's entire being had been at the time of his first emergence into awareness. I wish to join you, to understand you completely, the shoot signaled.

Do as you like, Cub responded indifferently.

OX attuned his subcircuits to the nervous impulses of living matter, as he had so recently mastered with Ornet. He slid the shoot over to merge.

There was a period of adjustment, for though the principle of functioning was similar, between Ornet and Cub, the detail differed. Then awareness focused.

It was a maelstrom. Rational misgivings warred with unattainable urges. The picture of a naked-Cub-species female formed, her arms and legs outstretched... dissipated in an aura of revulsion... re-formed.

OX watched, felt, experienced. Now he, too, felt those amazing urges. The attraction/repulsion of the reproduction/death complex; the need to overtake, to grasp, to envelop, to penetrate -- countered by inability, confusion, and guilt. Desire without opportunity, force without mechanism. Compulsion so great it threatened to nullify survival itself. Emotion.

OX twisted out of phase with such an effort that he carried the entire enclave into another frame. His system was in terrible disarray; his circuits warred with each other.

But now he understood the spots' need to reproduce their kinds. He knew what emotion was. Having discovered that, he was unable to eliminate it from his system; the profound new circuits were part of his pattern.

But OX realized that his survey was still incomplete. He had learned marvelous and dismaying new things -- but that only increased the need to learn the rest. Perhaps little of significance remained, and there were nonsurvival aspects to the continuation of this search -- but he had to do it. Survival and emotion drove him.

He searched out Mach, the wild machine.

OX antic.i.p.ated resistance, but Mach was quiescent. Perhaps it was waiting to ascertain the nature of this new attack. OX formed a shoot-image of it, then cautiously phased in.

This was dangerous because the machine, unlike the living spots, had certain pattern-aspects. It was aware of the elements, though its existence did not depend on them, and it could use them to make those special patterns that extended across frames. This ability was very limited, but this was one reason why OX had such trouble nullifying Mach's attacks. Mach could almost match OX's maneuverability across frames, provided that travel was restricted to adjacent or nearly adjacent ones. And the machine could drain the elements of so much energy that they would not serve a pattern-ent.i.ty for some time.

OX found the nerve circuits on the physical level of the machine, adapting to them as he had for Ornet and Cub. And slowly he became Mach.

The machine intellect was distinct from those of the living spots. Its impulses ran along metal conduits with appalling force and dealt with motors and transformers and switches and harsh chemical reactions rather than the subtle interactions of life or pattern. Yet it was sentient.

This was Mach -- and now OX understood. The machine had needs fully as compelling as those of the other ent.i.ties. Its prime motive was similar to theirs: SURVIVE. But it required energy transformed from matter by more brutal processes. Most of the physical substances it could obtain from its environment, but a few were in critical shortage here in the enclave.